Power management in electric vehicles

ABSTRACT

Various techniques described herein relate to electric vehicle power management system for managing a plurality of battery modules in a battery pack. Such electric vehicle power management system may include a plurality of battery management systems corresponding to a plurality of battery modules, and an energy management system for managing the plurality of battery management systems. The energy management system and the plurality of battery management systems may adopt master-slave wireless communication, and may use a single wireless frequency channel or a plurality of assigned wireless frequency channels.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of Non-Provisional U.S.application Ser. No. 14/748,210, filed Jun. 23, 2015, which claimspriority to U.S. Provisional Patent Application No. 62/133,991, filedMar. 16, 2015, and U.S. Provisional Patent Application No. 62/150,848,filed Apr. 22, 2015, the disclosures of which are hereby incorporated byreference in their entireties for all purposes.

FIELD OF THE INVENTION

The present invention relates to a power management systems for electricbatteries, for example, batteries within electric vehicle motors andother electric devices.

BACKGROUND OF THE INVENTION

Battery charging and power management technologies are an important partof the development of new electric battery-powered devices, such aselectric vehicles. For example, a plurality of battery modules may bethe power source of an electric vehicle and may play an important rolein the operation of the electric vehicle. Effective management andmonitoring of the battery may be a critical technology, and thus thebattery management system becomes an essential part of the electricvehicle. Battery management systems in electric vehicles may monitorbattery voltage, current, temperature, and other battery parameters andconditions necessary to ensure the effective operation of the battery.Such data may be stored and provided to various control circuits andsystems within the battery pack and/or within the electric device (e.g.,a vehicle control unit of an electric vehicle). In some cases, batterypacks may use pluralities of replaceable battery modules, creatingcomplications and difficulties for ongoing monitoring and management ofthe battery modules.

BRIEF SUMMARY OF THE INVENTION

In view of the above, the present invention relates to power managementsystems for electric devices, such as electric vehicles.

Certain aspects of the present invention relate to power managementsystem for electric vehicle. Electric vehicle power management systemsmay be used to manage a plurality of battery modules, and each batterymodule in the plurality of battery modules may comprises one or morebattery cells. Such electric vehicle power management systems maycomprise a plurality of battery management systems (BMS), wherein eachbattery management system in the plurality of battery management systems(BMS) is connected with a corresponding battery module for managing oneor more battery cells in the corresponding battery module. An energymanagement system (EMS) may manage the plurality of battery managementsystems. The electric vehicle power management system may furthercomprise a wireless data channel consisting of one or more wirelessfrequency channels for data communication between the energy managementsystem and the plurality of battery management systems. The energymanagement system also may include an energy management processor and anenergy management communication module. Each battery management systemmay include a battery management processor and a battery managementcommunication module, and also may be provided with a unique batterymanagement system address. The energy management communication modulemay use the wireless frequency channel to simultaneously send a commandto each of the battery management systems, and the command may carry anaddress identifying a currently selected battery management system. Eachof the battery management communication modules may receive the commandfrom the energy management communication module, and may use theirrespective battery management processors to determine whether or not toprocess and answer the received command based on the address in thecommand. The battery management processor of the currently selectedbattery management system may determine that judges that there is a needto process and answer the received command, and may then process andrespond to the received command.

According to additional aspects of the present invention, electricvehicle power management systems may be provided. The electric vehiclepower management systems may be used for managing a plurality of batterymodules, wherein each battery module in the plurality of battery modulescomprises one or more battery cells. The electric vehicle powermanagement systems may comprises a plurality of battery managementsystems (BMS), wherein each battery management system in the pluralityof battery management systems corresponds to a battery module, and eachbattery management system may be used for managing one or more batterycells in the battery module. An energy management system (EMS) maymanage the plurality of battery management systems. Electric vehiclepower management systems may further comprise a wireless data channel,the wireless data channel consists of a plurality of wireless frequencychannels, and each battery management system in the plurality of batterymanagement systems may use a corresponding wireless frequency channel inthe plurality of wireless frequency channels to communicate with theenergy management system. The energy management system may include anenergy management communication module, and each battery managementsystem in the plurality of battery management systems (BMS) may includea battery management communication module. The energy managementcommunication module may use the wireless frequency channels to send acommand to one battery management system in the plurality of batterymanagement systems, or to multiple battery management systems in theplurality of battery management systems simultaneously. The one ormultiple battery management systems in the plurality of batterymanagement systems may receive the command through their respectivebattery management communication modules, process and respond to thecommand after receiving the command.

According to the further aspects of the present invention, battery packsof electric vehicles may be provided. Such battery packs may include aplurality of battery modules, and the battery packs may use the electricvehicle power management system according to the embodiments describedherein.

In still further aspects of the present invention, electric vehicles maybe provided, the electric vehicles including the battery pack of theelectric vehicle and/or electric vehicle power management systemsaccording to the embodiments described herein.

Various embodiments described herein may have certain advantages overtechniques, for example, avoiding large numbers of wirings in electricvehicle battery packs and thus saving space with such battery packs.Additionally, less or none of the communication wire joints may berequired in some cases, and thus battery module groups may be moreconvenient to replace, and vehicle stability problems resulting fromloss of communication with battery modules may be more effectivelyprevented.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be further described in detail with referenceto the accompanying drawings

FIG. 1A shows a data exchanging diagram of an electric vehicle powermanagement system in accordance with one or more embodiments of thepresent invention.

FIG. 1B shows a data exchanging diagram of the electric vehicle powermanagement system in accordance with one or more embodiments of thepresent invention.

FIG. 2 shows a hardware module diagram of the electric vehicle powermanagement system in accordance with one or more embodiments of thepresent invention.

FIG. 3A shows an internal main communication flow diagram of a batterypack using the electric vehicle power management system in accordancewith one or more embodiments of the present invention.

FIG. 3B shows an internal implementation flow diagram of the batterypack using the electric vehicle power management system in accordancewith one or more embodiments of the present invention.

FIG. 4 shows an internal communication flow schematic diagram of abattery pack using the electric vehicle power management system inaccordance with one or more embodiments of the present invention.

FIG. 5 shows an example block diagram for a computing system upon whichvarious features of the present disclosure may be provided.

DETAILED DESCRIPTION

Embodiments of the electric vehicle power management system of thepresent invention will be described below with reference to theaccompanying drawings.

In the following description, for the purposes of explanation, numerousspecific details are set forth in order to provide a thoroughunderstanding of various embodiments of the present invention. It willbe apparent, however, to one skilled in the art that embodiments of thepresent invention may be practiced without some of these specificdetails. In other instances, well-known structures and devices are shownin block diagram form.

The ensuing description provides exemplary embodiments only, and is notintended to limit the scope, applicability, or configuration of thedisclosure. Rather, the ensuing description of the exemplary embodimentswill provide those skilled in the art with an enabling description forimplementing an exemplary embodiment. It should be understood thatvarious changes may be made in the function and arrangement of elementswithout departing from the spirit and scope of the invention as setforth in the appended claims.

Specific details are given in the following description to provide athorough understanding of the embodiments. However, it will beunderstood by one of ordinary skill in the art that the embodiments maybe practiced without these specific details. For example, circuits,systems, networks, processes, and other components may be shown ascomponents in block diagram form in order not to obscure the embodimentsin unnecessary detail. In other instances, well-known circuits,processes, algorithms, structures, and techniques may be shown withoutunnecessary detail in order to avoid obscuring the embodiments.

Also, it is noted that individual embodiments may be described as aprocess which is depicted as a flowchart, a flow diagram, a data flowdiagram, a structure diagram, or a block diagram. Although a flowchartmay describe the operations as a sequential process, many of theoperations can be performed in parallel or concurrently. In addition,the order of the operations may be re-arranged. A process is terminatedwhen its operations are completed, but could have additional steps notincluded in a figure. A process may correspond to a method, a function,a procedure, a subroutine, a subprogram, etc. When a process correspondsto a function, its termination can correspond to a return of thefunction to the calling function or the main function.

Various embodiments of the present invention will be described belowwith reference to the drawings constituting a part of the description.It should be understood that, although terms representing directions areused in the present invention, such as “front”, “rear”, “upper”,“lower”, “left”, “right”, and the like, for describing various exemplarystructural parts and elements of the present invention, these terms areused herein only for the purpose of convenience of explanation and aredetermined based on the exemplary orientations shown in the drawings.Since the embodiments disclosed by the present invention can be arrangedaccording to different directions, these terms representing directionsare merely used for illustration and should not be regarded aslimitation. Wherever possible, the same or similar reference marks usedin the present invention refer to the same components.

The term “computer-readable medium” includes, but is not limitednon-transitory media such as portable or fixed storage devices, opticalstorage devices, and various other mediums capable of storing,containing or carrying instruction(s) and/or data. A code segment orcomputer-executable instructions may represent a procedure, a function,a subprogram, a program, a routine, a subroutine, a module, a softwarepackage, a class, or any combination of instructions, data structures,or program statements. A code segment may be coupled to another codesegment or a hardware circuit by passing and/or receiving information,data, arguments, parameters, or memory contents. Information, arguments,parameters, data, etc. may be passed, forwarded, or transmitted via anysuitable means including memory sharing, message passing, token passing,network transmission, etc.

Furthermore, embodiments may be implemented by hardware, software,firmware, middleware, microcode, hardware description languages, or anycombination thereof. When implemented in software, firmware, middlewareor microcode, the program code or code segments to perform the necessarytasks may be stored in a computer-readable medium. A processor(s) mayperform the necessary tasks.

Various techniques (e.g., systems, circuits, methods, non-transitorycomputer-readable storage memory storing a plurality of instructionsexecutable by one or more processors, etc.) are described hereinrelating to electric vehicle power management system for managing aplurality of battery modules in a battery pack. Such electric vehiclepower management system may include a plurality of battery managementsystems corresponding to a plurality of battery modules, and an energymanagement system for managing the plurality of battery managementsystems. The energy management system and the plurality of batterymanagement systems may adopt master-slave wireless communication, andmay use a single wireless frequency channel or a plurality of assignedwireless frequency channels.

In certain embodiments described herein, a plurality of batterymanagement systems (BMS) 132.1, 132.2, . . . , 132.n corresponding to aplurality of battery modules 131.1, 131.2, . . . , 131.n may communicatewith an energy management system (EMS) 111 through wireless datachannels.

FIG. 1A shows a data exchanging diagram of an electric vehicle powermanagement system in accordance with one or more embodiments, and FIG.1B shows another example of a data exchanging diagram of an electricvehicle power management system in accordance with one or moreembodiments. As shown in FIG. 1A and FIG. 1B, power management systems100 described herein may manage and monitor a battery pack 101. Thebattery pack 101 may include a plurality of battery modules 131.1,131.2, . . . , 131.n, each battery module 131.i (i=1, 2, n) beingconnected with one BMS 132.i (i=1, 2, . . . n) for managing one or morebattery cells in the corresponding battery module 131.i. A batterymodule 131.i and its corresponding BMS 132.i may form a replaceablebattery module group 112.i (i=1, 2, . . . n), and in the case ofmalfunction of the currently used battery module group 112.i, may bereplaced by an alternative battery module group.

The power management system 100 may further include an energy managementsystem (EMS) 111, the EMS 111 may be used for managing the plurality ofBMS 132.1, 132.2, . . . , 132.n, and the EMS 111 may be connected withthe BMS 132.1, 132.2, . . . , 132.n through wireless data channels 113,114. Since connection is achieved by the wireless data channels 113,114, a large number of wirings are avoided, and the overall space of thebattery pack 101 may be reduced. Meanwhile, as no communication wirejoint may be needed, the problem of communication wire joint lossresulting from replacement of the battery module group 112.i may bepotentially avoided, and thus the stability may be reinforced.

FIG. 2 shows a hardware module diagram of the electric vehicle powermanagement system in accordance with various embodiments. In thisexample, each BMS 132.i is provided with a battery management processor211.i (i=1, 2, . . . n), a battery management memory 212.i (i=1, 2, . .. n), a battery management communication module 213.i (i=1, 2, . . . n),a voltage detection circuit 214.i (i=1, 2, . . . n) and a temperaturedetection circuit 215.i (i=1, 2, . . . n). Each BMS 132.i may detectssuch data as the voltage and temperature of the corresponding batterymodule 131.i in real time via the voltage detection circuit 214.i andthe temperature detection circuit 215.i, and may store this data in thebattery management memory 212.i. The EMS 111 may be provided with anenergy management processor 201, an energy management memory 202 and anenergy management communication module 203.

In some embodiments, a communication manner of a master-slavearchitecture may be used when the wireless data channels 113, 114 areused to carry out internal communication of the battery pack 101. Forexample, the EMS 111 may be used as a master control terminal and eachBMS 132.i may be used as a slave terminal. The EMS 111 serving as themaster control terminal may determine which BMS 132.i replies, to avoida potential conflict resulting from the uncertainty of which BMS 132.ineeds to communicate with the EMS 111, so as to avoid information jam.Meanwhile, due to the communication manner of the master-slavearchitecture, the BMS 132.1, 132.2, . . . , 132.n need notintercommunicate and may be mutually independent, so that the entirepower management system will not be affected by one abnormal BMS in theplurality of BMSs.

To manage each BMS 132.i, the EMS 111 may need to periodically orcontinuously collect from each BMS 132.i the information of itscorresponding battery module 131.i. In the example shown in FIG. 1A, thewireless data channel 113 used by the EMS 111 consists of one wirelessfrequency channel, which may be simultaneously connected with the EMS111 and the plurality of BMS 132.1, 132.2, . . . , 132.n in order to tosave resources. Each BMS 132.i may be permanently provided with a uniqueBMS address ID.i (i=1, 2, . . . n). By providing the address ID.iidentifying a currently selected BMS in the communication information,the EMS 111 may communicate with one currently selected BMS at one timeand after finishing communication with the currently selected BMS, itmay communicate with a next selected BMS, and so on, until each BMS inthe plurality of BMSs has communicated with the EMS 111. After one suchround of communication is finished, a next round of communication may becarried out. In some embodiments, if only one wireless frequency channelis used, the conflict caused by simultaneous communication between theplurality of BMSs and the EMS 111 may be effectively avoided by thiscommunication method.

The internal communication flow of the battery pack 101 using the powermanagement system of the embodiment as shown in FIG. 1A will bedescribed below in detail with reference to FIG. 1A, FIG. 2 and FIG. 3A.However, it should be understood that techniques described in referenceto these figures are not limited to the specific systems shown in FIG.1A and FIG. 2, but may be used in the various other embodimentsdescribed herein.

In step 301, at first, prior to communication, a unique BMS address ID.i(i=1, 2, . . . n) may be permanently provided to each BMS 132.i, and theID information of all the BMSs may be stored in the energy managementmemory 202 of the EMS 111.

In step 302, prior to each round of communication, the EMS 111 may set acommunication interval time, the communication interval time herein mayrefer to the time interval from the finishing moment of thecommunication between the energy management system 111 and the currentlyselected BMS to the starting moment of the communication between theenergy management system 111 and a next selected BMS.

Step 303 to step 306 show an abnormality verification process before theEMS 111, which may send a data command to the currently selected batterymanagement system 132.j (j=1, 2, . . . n).

In step 303, the energy management processor 201 of the EMS 111 maycontrol the energy management communication module 203 to simultaneouslysend a verification signal carrying the address ID.j identifying thecurrently selected BMS 132.j to the battery management communicationmodules 213.1, 213.2, . . . 213.n of all the BMS 132.1, 132.2, . . .132.n through the wireless data channel 113.

In step 304, after each battery management communication module 213.ireceives the verification signal from the energy managementcommunication module 203, each battery management processor 211.i maydetermine whether to answer the verification signal according to theID.j in the verification signal. Specifically, the battery managementprocessor 211.i may compare/check whether the ID.j in the verificationsignal is consistent with the ID stored in the memory 212.i. If so, theBMS.i may enter step 305 to serve as the currently selected BMS 132.j toreply to the EMS 111 with a verification answer signal. If not, theBMS.i may discard the verification signal.

In step 306, the EMS 111 may judge/determined whether there isabnormality associated with the BMS according to the verification answersignal. The abnormal conditions may be, for example, that the EMS 111did not receive the verification answer signal of the currently selectedBMS 132.j within a preset time, or that the verification answer signalreceived by the EMS 111 is a messy code, or that there is an errormarker in the verification answer signal received by the EMS 111, etc.If the EMS 111 determines that there is some abnormality associated withthe BMS, the EMS 111 may enter a fault diagnosis flow 307.

In the fault diagnosis flow 307, the EMS 111 may first judge the faulttype, then may determine whether to start an alarm mechanism based onthe fault type. If an alarm mechanism is started, the EMS 111 may sendalarm information to a vehicle control unit (VCU), which may performfollow-up fault processing, after which the EMS 111 may return to themain communication flow to carry out step 308. If it is judged thatthere is no need to start an alarm mechanism, the EMS 111 may terminatethe fault diagnosis flow 307 and return to the main communication flow.By providing the abnormality verification process, problems arising inthe process of using the wireless data channel may be effectivelymonitored, so as to process the fault timely and avoid the influence onthe follow-up command and answer processing.

If the EMS 111 verifies that there is no abnormality, a request datasending flow of step 308 to step 310 may be carried out.

Specifically, in step 308, the energy management processor 201 of theEMS 111 may control the energy management communication module 203 tosimultaneously send a request data command to the battery managementcommunication modules 213.1, 213.2, . . . 213.n of all the BMSs 132.1,132.2, . . . 132.n through the wireless data channel 113. The requestdata command may include, for example, a starting marker, the ID.jidentifying the currently selected BMS 132.j, a command which requeststhe currently selected BMS 132.j to send such common information as thevoltage, current, temperature, etc. of the corresponding battery module131.j following the currently selected ID.j, and/or termination marker.

In step 309, after each battery management communication module 213.ireceives the request data command from the energy managementcommunication module 203, each battery management processor 211.i maydetermine whether to process and answer the command based on the ID.j inthe request data command. During operation, each battery managementcommunication module 213.i often does not need to completely receive therequest data command and may only need to receive the command to theID.j portion which identifies the currently selected BMS 132.j. After abattery management processor 211.i determines that the ID.j isconsistent with the ID thereof, the battery management processor maycontinue to receive the command until the command ends and/or atermination marker is received. If the ID.j is not consistent with theID thereof, the battery management processor need not continue toreceive the command and may discards the request data command. In thisway, the communication efficiency may be effectively improved.

In step 310, the battery management processor 211.j of the currentlyselected BMS 132.j may control the currently selected battery managementcommunication module 213.j to reply to the EMS 111 with request datathrough the wireless data channel 113. after it is determined that thereis a need to process and answer the request data command. In these andother embodiments, battery management processors 211 of the BMSs 132 mayperform the various functions described herein via hardware circuitryand/or via computer-readable media storing computer-executable softwareinstructions to perform the described functions.

After the currently selected BMS 132.j replies to the EMS 111 with therequest data, step 311 is carried out, in which the energy managementprocessor 201 of the EMS 111 may determine whether to implement anoperation on the currently selected BMS 132.j. If so, an implementationflow such as in step 312 may be carried out. The implementing operationherein refers to that the EMS 111 needs to modify the parameters of thecurrently selected BMS 132.j or needs the currently selected BMS 132.jto reply with additional information, such as, for example, a batterysetting parameter record, etc. The additional information may includeany information relating to the previous or current states of theselected BMS 132.j, but need not include the previously transmittedcommon information (e.g., voltage and temperature).

The specific flow of step 312 is illustrated in the internalimplementation flow diagram of the battery pack using the firstembodiment as shown in FIG. 3B. In this example, in step 3121, the EMSmay send an implementation command carrying the address ID.j of thecurrently selected BMS 132.j to each BMS 132.i. In step 3122, each BMS132.i may independently determine whether there is a need to answer theimplementation command according to the ID. These individualdeterminations may be similar to the method in step 309 discussed above,in which the BMS 132.i may determine whether there is a need to answerthe request data command according to the ID. In step 3123, thecurrently selected BMS 132.j may receive and implement the command.After the currently selected BMS 132.j implements the command, in step3124, the main communication flow as shown in FIG. 3A may be carried outagain.

After the currently selected BMS 132.j has processed and responded tothe command sent for the currently selected BMS 132.j, the communicationof the EMS 111 with the currently selected BMS 132.j may be deemed to befinished, and step 313 is carried out. In step 313, the energymanagement processor 201 of the EMS 111 may determine whether is hasfinished sending a corresponding command to each one of the plurality ofbattery modules 131.1, 131.2, . . . , 131.n. If not, step 314 is carriedout, in which the EMS 111 updates the address ID identifying a currentlyselected BMS to ID.j+1, so as to select a next currently selected BMS132.j+1. After waiting for the interval time set in step 302, thecommunication with the next currently selected BMS 132.j+1 then may bestarted in step 303. Thus, the communication of each BMS 132.i may bedetermined by the EMS 111, so that the conflict resulting from thesimultaneous reply to the EMS 111 by a plurality of BMSs may beeffectively avoided.

In some cases, the EMS 111 may continuously and sequentially update theaddress ID of a current BMS to continuously select a next currentlyselected BMS until it has sent a corresponding command to each one ofthe plurality of BMS 132.1, 132.2, . . . , 132.n. It should be notedthat, the sequentially updating herein need not be limited to that theplurality of BMS 132.1, 132.2, . . . , 132.n that needs to be sequencedaccording to a certain fixed sequence for communication, but refers tothat the EMS non-repeatedly communicate with each one of the pluralityof BMSs in each round of communication.

When the EMS 111 has finished sending a corresponding command to eachone of the plurality of BMSs 132.1, 132.2, . . . , 132.n, it maydetermine in step 313 that it has finished the current round ofcommunication. At this point, the process may return back to step 302 tostart a new round of communication.

FIG. 1B shows another data exchanging diagram of the electric vehiclepower management system according to various embodiments. Thecommunication manner of the master-slave architecture is also adopted inthis example. The difference from the embodiment shown in FIG. 1A liesin that, in this example, the wireless data channel 114 consists of aplurality of wireless frequency channels 114.1, 114.2, . . . , 114.n.Each one of the wireless frequency channels 114.1, 114.2, . . . , 114.nmay correspond to a specific BMS 132.i (i=1, 2, . . . n), and the EMS111 may communicate with each BMS 132.i by using the wireless frequencychannel 114.i (i is equal to 1, 2, . . . n) corresponding to that BMS132.i (i=1, 2, . . . n). Since each BMS 132.i may be provided with aunique wireless frequency channel 114.i, even if multiple

BMSs communicate with the EMS 111 at the same time, communicationcollisions and/or conflict may be avoided. Moreover, addresses (ID.i)for distinguishing the battery modules, which are optional in thisexample, may be stored in the EMS 111. The EMS 111 may associate theaddress (ID.i) of each battery module with its corresponding wirelessfrequency channel 114.i, and in this way, the EMS 111 may send thecommands of the battery modules to the battery modules through thecorresponding wireless channels.

The internal communication flow of the battery pack 101 using theembodiment as shown in FIG. 1B will be described below in detail withreference to FIG. 2 and FIG. 4. However, it should be understood thattechniques described in reference to these figures are not limited tothe specific systems shown in FIG. 1B and FIG. 4, but may be used in thevarious other embodiments described herein.

In step 401, at first, prior to communication, each BMS 132.i may bepermanently provided with a unique BMS address ID.i (i=1, 2, . . . n)and a unique wireless frequency channel 114.i, and the ID information ofall the BMSs and the information of the corresponding wireless frequencychannels may be stored in the energy management memory 202 of the EMS111.

In step 402, prior to each round of communication, the EMS 111 may set acommunication interval time, the communication interval time herein mayrefer to the time interval from the finishing moment of the currentcommunication between the EMS 111 and the BMSs to the starting moment ofthe next communication between the EMS 111 and the BMSs. The energymanagement processor 201 may control the duration of the time intervalas required.

Step 403 to step 405 show an abnormality verification process before theEMS 111 collects from a BMS 132.i the information of its correspondingbattery module 131.i. Specifically, in step 403, the energy managementprocessor 201 of the EMS 111 may select multiple BMSs that needcommunication to simultaneously communicate with them, the energymanagement communication module 203 may send a verification signal tothe battery management communication modules of the selected BMSsthrough their respective wireless channels. It should be noted that themultiple selected BMSs herein may or may not be all the BMSs in thebattery pack 101. For example, the EMS 111 also may only select one BMS132.i and send the verification signal to the BMS 132.i through itscorresponding wireless channel 114.i.

Since each wireless channel 114.i corresponds to a single BMS 132.i inthis example, only the BMS 132.i using the wireless channel 114.i mayreceive the verification signal sent via the wireless channel 114.i. Instep 404, after receiving the verification signal, one or more batterymanagement communication modules may reply to the EMS 111 with theirverification answer signals through their respective wireless channels.If the EMS 111 selected multiple BMSs to simultaneously communicate withthem, the EMS 111 may send a same verification to these BMSssimultaneously. When these BMSs reply with verification answer signals,the EMS 111 may distinguish these verification answer signals from themultiple BMSs via their corresponding wireless frequency channels. Ofcourse, in other embodiments, other methods can be used to distinguishthe verification answer signals from the multiple BMSs. For example, theEMS 111 may send to each BMS.i a verification signal added with itscorresponding address ID.i and each BMS.i may reply to the EMS 111 witha verification answer signal added with its corresponding address ID.i.In other examples, the EMS 111 may send to the multiple BMSs a sameverification signal, but each BMS.i may reply to the EMS 111 with averification answer signal added with its corresponding address

In step 405, the EMS 111 may determine whether there is abnormalityassociated with one or more BMS(s) based on verification answersignal(s) received from the BMS(s). If the energy management system 111determines that there is an abnormality, the energy management system111 may enter a fault diagnosis flow 406. The general abnormalconditions and the fault diagnosis flow 406 may be the same as thosediscussed above in reference to FIG. 1A.

If the EMS 111 verifies that there is no abnormality, a request datasending flow of step 407 to step 408 will be carried out. For example,the EMS 111 may send a request data command to the previously selectedBMSs through their respective wireless frequency channels, and theselected BMSs may reply to the EMS with request data through theirrespective wireless frequency channels. The way the EMS 111 sends therequest data command and the BMSs reply to the EMS 111 with request dataare similar to the way used by the abnormality verification processdescribed above.

After the selected BMSs have replied to the EMS with request datathrough their respective wireless frequency channels, step 409 maycarried out. In step 409, the energy management processor 201 of the EMS111 may determine whether there is a need to implement operations on theselected BMSs. If so, in step 410 and step 411, the EMS 111 may sendimplementation commands to the BMSs through their respective wirelessfrequency channels 114.i, and the BMSs may receive and implement theimplementation commands. In these and other embodiments, the energymanagement processor 201 of the EMS 111 may perform the variousfunctions described herein via hardware circuitry and/or viacomputer-readable media storing computer-executable softwareinstructions to perform the described functions.

After the selected BMSs have finished processing and answering, thecurrent communication of the EMS 111 with the BMSs is deemed to befinished, and after waiting for the interval time set in step 402, thenext communication of the EMS 111 with the BMSs may be started from step402.

As shown in FIG. 1A, FIG. 1B and FIG. 2, the battery pack 101 maycommunicate with various peripheral equipment of the battery packthrough the EMS 111. Specifically, the energy management communicationmodule 203 of the EMS 111 may send communication data to certainperipheral equipment, or may receive the communication data fromperipheral equipment, through an external data bus 207. The peripheralequipment in such cases may include, for example, a vehicle control unit(VCU) 204, a charging unit (charger) 206, and a user interface (UI) 205.The external data bus 207 may be connected with the communicationmodules of such peripheral equipment.

In some embodiments, an external data bus 207 may adopt a high-speedwired data channel, and the communication mode can select a CAN busmanner or the like. In other examples, the external data bus 207 mayadopt a wireless communication channel.

In some cases, the wireless data channels 113 or 114 connecting to theinterior of the battery pack 101 may be mutually independent from theexternal data bus 207. Accordingly, the communication stability of thepower management system and the vehicle control unit (VCU) may beeffectively guaranteed in such cases, and the interference on thecommunication stability of the VCU 204 with other systems may be moreeffectively avoided.

Additional embodiments may provide a battery pack 101 of an electricvehicle which includes the above-mentioned plurality of battery modules131.1, 131.2, . . . , 131.n, and the battery pack 101 uses theabove-mentioned electric vehicle power management system.

Further embodiments also may provide an electric vehicle including theabove-mentioned battery pack 101, battery modules 131, etc.

Referring now to FIG. 5, an example block diagram for a computer systemor other computer device 500 which may be integrated into and/oroperatively connected to the battery management systems (BMSs), energymanagement systems (EMSs), vehicle control units (VCUs) describedherein, as well as any other components described above. One or morecomputer systems or other computer devices 500 may control one or moreaspects of the electric devices and/or components described above. Forexample, one or more computer devices 500 may be used to implement thevarious battery management systems 132 and battery module groups 112,energy management systems 111, vehicle control units 204, userinterfaces 205, charging units 206 described above. Accordingly, suchcomponents may include some or all of the features described below inreference to computer device 500. In some examples, the computer systemor other computer devices 500 may include a tablet computer, personaldata assistant, smartphone, gaming console, and/or a dedicated computersystem for controlling the electric vehicle. Any particular one of thepreviously-described computing devices may be wholly or at leastpartially configured to exhibit features similar to the computer system500.

The computer device 500 is shown comprising hardware elements that maybe electrically coupled via a bus 502 (or may otherwise be incommunication, as appropriate). The hardware elements may include aprocessing unit with one or more processors 504, including withoutlimitation one or more general-purpose processors and/or one or morespecial-purpose processors (such as digital signal processing chips,graphics acceleration processors, and/or the like); one or more inputdevices 506, which may include without limitation a steering wheel, aclimate control button or other user input receiving buttons, and/or thelike; and one or more output devices 508, which may include withoutlimitation a presentation device (e.g., a computer screen), a GPS,and/or the like.

The computer system 500 may further include (and/or be in communicationwith) one or more non-transitory storage devices 510, which maycomprise, without limitation, local and/or network accessible storage,and/or may include, without limitation, a disk drive, a drive array, anoptical storage device, a solid-state storage device, such as a randomaccess memory, and/or a read-only memory, which may be programmable,flash-updateable, and/or the like. Such storage devices may beconfigured to implement any appropriate data stores, including withoutlimitation, various file systems, database structures, and/or the like.

The computer device 500 might also include a communications subsystem512, which may include without limitation a modem, a network card(wireless and/or wired), an infrared communication device, a wirelesscommunication device and/or a chipset such as a Bluetooth™ device,802.11 device, WiFi device, WiMax device, cellular communicationfacilities such as GSM (Global System for Mobile Communications), W-CDMA(Wideband Code Division Multiple Access), LTE (Long Term Evolution),etc., and/or the like. The communications subsystem 512 may permit datato be exchanged with a network (such as the network described below, toname one example), other computer systems, and/or any other devicesdescribed herein. In many embodiments, the computer system 500 willfurther comprise a working memory 514, which may include a random accessmemory and/or a read-only memory device, as described above.

The computer device 500 also may comprise software elements, shown asbeing currently located within the working memory 514, including anoperating system 516, device drivers, executable libraries, and/or othercode, such as one or more application programs 518, which may comprisecomputer programs provided by various embodiments, and/or may bedesigned to implement methods, and/or configure systems, provided byother embodiments, as described herein. By way of example, one or moreprocedures described with respect to the method(s) discussed above,and/or system components might be implemented as code and/orinstructions executable by a computer (and/or a processor within acomputer); in an aspect, then, such code and/or instructions may be usedto configure and/or adapt a general purpose computer (or other device)to perform one or more operations in accordance with the describedmethods.

A set of these instructions and/or code might be stored on anon-transitory computer-readable storage medium, such as the storagedevice(s) 510 described above. In some cases, the storage medium mightbe incorporated within a computer system, such as computer system 500.In other embodiments, the storage medium might be separate from acomputer system (e.g., a removable medium, such as flash memory), and/orprovided in an installation package, such that the storage medium may beused to program, configure, and/or adapt a general purpose computer withthe instructions/code stored thereon. These instructions might take theform of executable code, which is executable by the computer device 500and/or might take the form of source and/or installable code, which,upon compilation and/or installation on the computer system 500 (e.g.,using any of a variety of generally available compilers, installationprograms, compression/decompression utilities, etc.), then takes theform of executable code.

It will be apparent that substantial variations may be made inaccordance with specific requirements. For example, customized hardwaremight also be used, and/or particular elements might be implemented inhardware, software (including portable software, such as applets, etc.),or both. Further, connection to other computing devices such as networkinput/output devices may be employed.

As mentioned above, in one aspect, some embodiments may employ acomputer system (such as the computer device 500) to perform methods inaccordance with various embodiments of the disclosure. According to aset of embodiments, some or all of the procedures of such methods areperformed by the computer system 500 in response to processor 504executing one or more sequences of one or more instructions (which mightbe incorporated into the operating system 516 and/or other code, such asan application program 518) contained in the working memory 514. Suchinstructions may be read into the working memory 514 from anothercomputer-readable medium, such as one or more of the storage device(s)510. Merely by way of example, execution of the sequences ofinstructions contained in the working memory 514 may cause theprocessor(s) 504 to perform one or more procedures of the methodsdescribed herein.

The terms “machine-readable medium” and “computer-readable medium,” asused herein, may refer to any non-transitory medium that participates inproviding data that causes a machine to operate in a specific fashion.In an embodiment implemented using the computer device 500, variouscomputer-readable media might be involved in providing instructions/codeto processor(s) 504 for execution and/or might be used to store and/orcarry such instructions/code. In many implementations, acomputer-readable medium is a physical and/or tangible storage medium.Such a medium may take the form of a non-volatile media or volatilemedia. Non-volatile media may include, for example, optical and/ormagnetic disks, such as the storage device(s) 510. Volatile media mayinclude, without limitation, dynamic memory, such as the working memory514.

Example forms of physical and/or tangible computer-readable media mayinclude a floppy disk, a flexible disk, hard disk, magnetic tape, or anyother magnetic medium, a compact disc, any other optical medium, ROM,RAM, and etc., any other memory chip or cartridge, or any other mediumfrom which a computer may read instructions and/or code. Various formsof computer-readable media may be involved in carrying one or moresequences of one or more instructions to the processor(s) 504 forexecution. By way of example, the instructions may initially be carriedon a magnetic disk and/or optical disc of a remote computer. A remotecomputer might load the instructions into its dynamic memory and sendthe instructions as signals over a transmission medium to be receivedand/or executed by the computer system 500.

The communications subsystem 512 (and/or components thereof) generallywill receive signals, and the bus 502 then might carry the signals(and/or the data, instructions, etc. carried by the signals) to theworking memory 514, from which the processor(s) 504 retrieves andexecutes the instructions. The instructions received by the workingmemory 514 may optionally be stored on a non-transitory storage device510 either before or after execution by the processor(s) 504.

It should further be understood that the components of computer device500 can be distributed across a network. For example, some processingmay be performed in one location using a first processor while otherprocessing may be performed by another processor remote from the firstprocessor. Other components of computer system 500 may be similarlydistributed. As such, computer device 500 may be interpreted as adistributed computing system that performs processing in multiplelocations. In some instances, computer system 500 may be interpreted asa single computing device, such as a distinct laptop, desktop computer,or the like, depending on the context.

Examples of Certain Embodiments

In a first example embodiment, an electric vehicle power managementsystem (100) may be provided for managing a plurality of battery modules(131.1, 131.2, . . . , 131.n), wherein each battery module (131.i) (i=1,2, . . . , n) in the plurality of battery modules (131.1, 131.2, . . . ,131.n) comprises one or more battery cells, the electric vehicle powermanagement system comprises: a plurality of battery management systems(BMS) (132.1, 132.2, . . . , 132.n), wherein each battery managementsystem (132.i) (i=1, 2, . . . , n) in the plurality of batterymanagement systems (BMS) (132.1, 132.2, . . . , 132.n) is connected witha corresponding battery module (131.i) for managing one or more batterycells in the corresponding battery module (131.i); an energy managementsystem (EMS) (111), wherein the energy management system (111) managesthe plurality of battery management systems (132.1, 132.2, . . . ,132.n), wherein the electric vehicle power management system furthercomprises: a wireless data channel (113), the wireless data channel(113) consists of one wireless frequency channel for data communicationbetween the energy management system (111) and the plurality of batterymanagement systems (132.1, 132.2, . . . , 132.n); the energy managementsystem (111) is provided with an energy management processor (201) andan energy management communication module (203); each battery managementsystem (132.i) is provided with a battery management processor (211.i)and a battery management communication module (213.i); each batterymanagement system (132.i) is provided with a unique battery managementsystem address (ID.i); the energy management communication module (203)uses the wireless frequency channel to simultaneously send a command toeach battery management system (132.i), and the command carries anaddress (ID.j) identifying a currently selected battery managementsystem (132.j) (j=1, 2, . . . , n); each battery managementcommunication module (213.i) receives the command from the energymanagement communication module (203); each battery management processor(211.i) judges whether to process and answer the received commandaccording to the address (ID.j) in the command; the battery managementprocessor (211.j) of the currently selected battery management system(132.j) judges that there is a need to process and answer the receivedcommand, and then processes and answers the received command.

A second example embodiment may include the electric vehicle powermanagement system of the first example embodiment, wherein the commandis a request data command; when the battery management processor (211.j)of the currently selected battery management system (132.j) judges thatthere is a need to process and answer the received command, the batterymanagement communication module (213.j) of the currently selectedbattery management system (132.j) uses the wireless frequency channel toreply to the energy management system (111) with request data.

A third example embodiment may include the electric vehicle powermanagement system of the first example embodiment, wherein after thecurrently selected battery management system (132.j) finished processingand answering the command sent to the currently selected batterymanagement system (132.j), the energy management system (111) updatesthe address (ID.j+1) identifying a battery management system to beselected and select a next currently selected battery management system(132.j+1) accordingly.

A fourth example embodiment may include the electric vehicle powermanagement system of the third example embodiment, wherein the energymanagement system (111) continuously and sequentially updates theaddress identifying a battery management system to be selected and thuscontinuously select a next currently selected battery management systemuntil having finished sending a corresponding command to each one of theplurality of battery management systems (131.1, 131.2, . . . , 131.n).

A fifth example embodiment may include the electric vehicle powermanagement system of the first example embodiment, wherein beforesending the command to the battery management systems (131.1, 131.2, . .. , 131.n), the energy management system (111) sends a verificationsignal carrying the address (ID.j) identifying the currently selectedbattery management system (132.j) (j=1, n) to the battery managementsystems (131.1, 131.2, . . . , 131.n), and judges whether there isabnormality according to a verification answer signal replied by thecurrently selected battery management system (132.j) (j=1, n).

A sixth example embodiment may include the electric vehicle powermanagement system of the fifth example embodiment, wherein if the energymanagement system (111) judges that there is abnormality, the energymanagement system (111) enters a fault diagnosis flow.

A seventh example embodiment may include the electric vehicle powermanagement system of the third example embodiment, wherein the energymanagement system (111) sets a communication interval time, so that theprocessor (201) of the energy management system (111) controls the timeinterval from the finishing moment of the communication with thecurrently selected battery management system (132.j) to the startingmoment of the communication with a next selected battery managementsystem (132.j+1).

In an eighth example embodiment, an electric vehicle power managementsystem (100) used for managing a plurality of battery modules (131.1,131.2, . . . , 131.n) may be provided, wherein each battery module(131.i) (i=1, n) in the plurality of battery modules (131.1, 131.2, . .. , 131.n) comprises one or more battery cells, the electric vehiclepower management system comprises: a plurality of battery managementsystems (BMS) (132.1, 132.2, . . . , 132.n), wherein each batterymanagement system (132.i) (i=1, 2, . . . , n) in the plurality ofbattery management systems (132.1, 132.2, . . . , 132.n) corresponds toa battery module (131.i), and each battery management system (132.i) isused for managing one or more battery cells in the battery module(131.i); an energy management system (EMS) (111), wherein the energymanagement system (111) manages the plurality of battery managementsystems (132.1, 132.2, . . . , 132.n), wherein the electric vehiclepower management system further comprises: a wireless data channel(114), the wireless data channel (114) consists of a plurality ofwireless frequency channels (114.1, 114.2, . . . , 114.n), and eachbattery management system (132.i) in the plurality of battery managementsystems (132.1, 132.2, . . . , 132.n) uses a corresponding wirelessfrequency channel (114.i) in the plurality of wireless frequencychannels (114.1, 114.2, . . . , 114.n) to communicate with the energymanagement system (111); the energy management system (111) is providedwith an energy management communication module (203); each batterymanagement system (132.i) in the plurality of battery management systems(BMS) (132.1, 132.2, . . . , 132.n) is provided with a batterymanagement communication module (213.i); the energy managementcommunication module (203) uses the wireless frequency channels to senda command to one battery management system (132.i) in the plurality ofbattery management systems or to multiple battery management systems inthe plurality of battery management systems simultaneously; the one ormultiple battery management systems in the plurality of batterymanagement systems receive the command through their respective batterymanagement communication modules, and process and answer the commandafter receiving the command.

A ninth example embodiment may include the electric vehicle powermanagement system of the eighth example embodiment, wherein each one ofthe plurality of wireless frequency channels (114.1, 114.2, . . . ,114.n) corresponds to a unique battery management system address (ID).

A tenth example embodiment may include the electric vehicle powermanagement system of the eighth example embodiment, wherein beforesending the command to the one or multiple battery management systems,the energy management system (111) sends a verification signal to theone or multiple battery management systems and judges whether there isabnormality according to verification answer signal(s) replied by theone or multiple battery management systems.

An eleventh example embodiment may include the electric vehicle powermanagement system of the tenth eighth example embodiment, wherein if theenergy management system (111) judges that there is abnormality, theenergy management system (111) enters a fault diagnosis flow.

A twelfth example embodiment may include the electric vehicle powermanagement system of the first example embodiment, wherein the energymanagement system (111) sets a communication interval time, so that theprocessor (201) of the energy management system (111) controls the timeinterval from the current communication with the battery managementsystems to the next communication with the battery management systems.

A thirteenth example embodiment may include the electric vehicle powermanagement system of any of the first through the twelfth exampleembodiments, further comprising: an external data bus (207), wherein theexternal data bus (207) is connected with the energy management system(111) for sending communication data from the energy management system(111) or receiving communication data from outside; the external databus is in communication connection with at least one of a vehiclecontrol unit (204), a charging unit (206) and a user interface (205), tocarry out bidirectional data communication.

A fourteenth example embodiment may include a battery pack (101) of anelectric vehicle, wherein the battery pack (101) comprises: a pluralityof battery modules (131.1, 131.2, . . . , 131.n), and the battery pack(101) uses the electric vehicle power management system of any of thefirst through the thirteenth example embodiments.

A fifteenth example embodiment may include an electric vehicle,comprising the battery pack (101) of the electric vehicle of thefourteenth example embodiment.

Although the present invention has been described with reference to thespecific embodiments shown in the drawings, it should be understood thatthe charging system and the charging method provided by the presentinvention can have a variety of variations without departing from thespirit, scope and background of the present invention. Those of ordinaryskill in the art should be still aware that, parameters in theembodiments disclosed by the present invention can be changed indifferent manners, and these changes shall fall within the spirit andscope of the present invention and the claims.

1. An electric vehicle power management system used for managing aplurality of battery modules, the electric vehicle power managementsystem comprising: a plurality of battery modules; a plurality ofbattery management systems, each said battery management systemcomprising a battery management processor, a battery managementcommunication module, and a unique battery management system address,wherein each of the plurality of battery management systems has abattery management system address, is connected to a correspondingbattery module and is configured to manage one or more battery cells ofits corresponding battery module; and an energy management systemcomprising an energy management processor and an energy managementcommunication module, wherein the energy management system isoperatively connected to each of the plurality of the battery managementsystems via a first wireless channel, and is configured to: set acommunication interval time select a first battery management systemfrom the plurality of battery management systems; transmit a firstcommand to each of the plurality of battery management systems using thefirst wireless channel, the first command carrying an addressidentifying the first battery management system and requesting data fromthe first battery management system; after the requested data from thefirst battery management system having been received or thecommunication time interval has expired, determine whether a datarequest has been sent to a second battery system; and when it isdetermined that a data request has not been sent to the second batterysystem, transmit a second command to each of the plurality of batterymanagement systems using the first wireless channel, the second commandcarrying an address identifying the second battery management system andrequesting data from the second battery management system; and, whereineach of the plurality of battery management systems is furtherconfigured to use its respective battery management processor andbattery management communication module to: receive a command from theenergy management system via the first wireless frequency channel;compare an address in the command identifying a selected batterymanagement system to its own battery management system address;determine, based on the comparison whether it is the selected batterymanagement system; and upon determining that it is the selected batterymanagement system, process and respond to the received command from theenergy management system.
 2. The electric vehicle power managementsystem of claim 1, wherein the address identifying the second batterymanagement system is not sequential to the address identifying the firstbattery management system such that there is a least one batterymanagement system having a battery management system address that isbetween the address identifying the second battery management and theaddress identifying the first battery management system.
 3. The electricvehicle power management system of claim 2, the energy management systemis further configured to determine whether each of the plurality of thebattery management systems has been sent a data request, and when it isdetermined that each of the plurality of the battery management systemshas been sent a data request, the energy management system is furtherconfigured to set the communication interval time again.
 4. (canceled)5. The electric vehicle power management system of claim 1, wherein theenergy management system is configured to continuously and sequentiallyupdate the address identifying one of the plurality of batterymanagement systems to be selected.
 6. The electric vehicle powermanagement system of claim 1, wherein the energy management system isfurther configured to: before transmitting the first command to each ofthe plurality of battery management systems, transmit a verificationsignal to each of the plurality of battery management systems, theverification signal carrying the address identifying the first selectedbattery management system; receive a response to the verification signalfrom the first selected battery management system; and determine whetherthere is an abnormality associated with the first selected batterymanagement system based on the response received to the verificationsignal.
 7. The electric vehicle power management system of claim 6,wherein the energy management system is further configured to: upondetermining that there is an abnormality associated with the firstselected battery management system, perform a fault diagnosis process.8. The electric vehicle power management system of claim 1, wherein theenergy management system is further configured to: identify a first timecorresponding to the termination of communications between the energymanagement system and the first selected battery management system; anddetermine a time for the transmission of the second command, based onthe identified first time and the communication interval time.
 9. Theelectric vehicle power management system of claim 1, further comprising:an external data bus connected to the energy management system, theexternal data bus configured to transmit communication data from theenergy management system and to receive communication data for theenergy management system, wherein the external data bus is configuredfor bidirectional communication with at least one of a vehicle controlunit, a charging unit, or a user interface. 10-18. (canceled)
 19. Amethod for managing a plurality of battery modules, the method beingimplemented by a electric vehicle power management system comprising: aplurality of battery modules; a plurality of battery management systems,each said battery management system comprising a battery managementprocessor, a battery management communication module, and a uniquebattery management system address, wherein each of the plurality ofbattery management systems has a battery management system address, isconnected to a corresponding battery module and is configured to manageone or more battery cells of its corresponding battery module; and anenergy management system comprising an energy management processor andan energy management communication module, wherein the energy managementsystem is operatively connected to each of the plurality of the batterymanagement systems via a first wireless channel; and wherein the methodcomprises: setting a communication interval time; selecting a firstbattery management system from the plurality of battery managementsystems; transmitting a first command to each of the plurality ofbattery management systems using the first wireless channel, the firstcommand carrying an address identifying the first battery managementsystem and requesting data from the first battery management system;after the requested data from the first battery management system havingbeen received or the communication time interval has expired,determining whether a data request has been sent to a second batterysystem; and when it is determined that a data request has not been sentto the second battery system, transmitting a second command to each ofthe plurality of battery management systems using the first wirelesschannel, the second command carrying an address identifying the secondbattery management system and requesting data from the second batterymanagement system; and, wherein each of the plurality of batterymanagement systems is further configured to use its respective batterymanagement processor and battery management communication module to:receive a command from the energy management system via the firstwireless frequency channel; compare an address in the commandidentifying a selected battery management system to its own batterymanagement system address; determine, based on the comparison whether itis the selected battery management system; and upon determining that itis the selected battery management system, process and respond to thereceived command from the energy management system.
 20. The method ofclaim 19, wherein the address identifying the second battery managementsystem is not sequential to the address identifying the first batterymanagement system such that there is a least one battery managementsystem having a battery management system address that is between theaddress identifying the second battery management and the addressidentifying the first battery management system.
 21. The method of claim19, further comprising determining whether each of the plurality of thebattery management systems has been sent a data request, and when it isdetermined that each of the plurality of the battery management systemshas been sent a data request, the energy management system is furtherconfigured to set the communication interval time again.
 22. The methodof claim 19, further comprising continuously and sequentially updatingthe address identifying one of the plurality of battery managementsystems to be selected.
 23. The method of claim 19, further comprisingbefore transmitting the first command to each of the plurality ofbattery management systems, transmitting a verification signal to eachof the plurality of battery management systems, the verification signalcarrying the address identifying the first selected battery managementsystem; receiving a response to the verification signal from the firstselected battery management system; and determining whether there is anabnormality associated with the first selected battery management systembased on the response received to the verification signal.
 24. Themethod of claim 19, further comprising: upon determining that there isan abnormality associated with the first selected battery managementsystem, performing a fault diagnosis process.
 25. The method of claim19, further comprising: identifying a first time corresponding to thetermination of communications between the energy management system andthe first selected battery management system; and determining a time forthe transmission of the second command, based on the identified firsttime and the communication interval time.
 26. The method of claim 19,wherein the electric vehicle power management system further comprisesan external data bus connected to the energy management system, whereinthe method further comprises: transmitting communication data from theenergy management system and to receive communication data for theenergy management system through the external data bus, wherein theexternal data bus is configured for bidirectional communication with atleast one of a vehicle control unit, a charging unit, or a userinterface.